This invention relates to an adjusting device for motorcar mirrors.
In U.S. Pat. No. 4,116,538 there is described a device for adjusting a motorcar mirror about two perpendicular axes, which device essentially consists of a cup-shaped housing having a raised edge, an adjusting ring mounted therein for tilting movement, which ring in any position is in sealing contact with the raised edge, and is supported in its center by means of a stiffening element extending along a ring diameter, and further having two mirror adjusting members engaging with the adjusting ring and being off-set relatively to each other through 90.degree., and drive means and transmission means, whose output shafts are operatively associated with the mirror adjusting members.
In this prior device, the drive and transmission means are formed by one single unit consisting of a motor which is reversible with regards to the direction of rotation, a clutch and two planetary transmission systems. This combined unit can be excellently accommodated in an instrument housing of relatively large dimensions, which therefore must in turn be housed in a mirror housing, likewise of large dimensions, mounted on an automotive vehicle. In order that the mirror adjusting device may also be suitable for smaller motorcars, and hence smaller mirror housings, it is desirable for them to be constructed as compact as possible, and so to avoid a relatively large combined drive-and-transmission unit.
In addition to reducing the size of the device proper, a further saving in space can be realized by placing the mirror adjusting device eccentrically relative to the mirror center, because mirror housings on motorcars have an asymmetrical form, with the depth of the housing being less accordingly as the distance from the sidewall of the motorcar is larger. When the mirror adjusting device is placed eccentrically there is the risk that the mirror turns about an axis perpendicular to the plane of the mirror and consequently comes to hang askew in its housing. This not only meets with esthetic objections, but also increases the risk that, when subjected to jolting or bumping, an edge of the mirror comes into contact with an edge of the mirror housing, which is undesirable. In order that an eccentric location of the mirror adjusting device may be possible, the device itself should have a high torsional stiffness.
In addition to a compact construction and a high torsional stiffness at positions it is also desirable that tilting axes should be provided, spaced as closely from the actual mirror surface as possible, this to make the space between the edge of the mirror housing on the motor vehicle and the edge of the mirror as small as possible.